Core A: Administrative Core The practices and procedures established during this first year will be continued. In addition, the Executive Committee will receive and review applications for new pilot projects. The external review committee will be assembled at the request of the Executive Committee in September, 1985. Core B: Neuroanatomy Core The peptidergic innervation of the esophagus (opossum) will be investigated using the new protocols developed. Quantitative methods will be introduced, using newly acquired ultramicrotomy equipment, to study absolute and relative ganglionic populations of different neurotransmitter types. The shunt fascicle-related ganglia and the shunt fascicles themselves will be studied. Feasibility studies will be continued with the ileum obstruction model in guinea pig and rat. In view of the fact that the previous studies have demonstrated smooth muscle hypertrophy after gut obstruction, we will inquire whether and to what extent myenteric neurons (including their processes) react. Do their responses differ according to morphological and/or neurotransmitter type? Core resources will continue to be provided to facilitate projects of Core Center investigators. Core C: Animal Core We will refine the computerized inventory system and continue to work with investigators as required by their needs. Karla Christensen will be trained to meet the potential needs of the DDCC investigators. She will handle the DDCC inventory, provide post-op care, special measurements and feeding as required.